typedef struct point3d{ //数据
      float x;
      float y;
      float z;
}Point3d;
void Point3d_print(const Point3d *pd{
      printf("%g,%g,%g",pd->x,pd->y,pd->z);
}

class Point3d{
      float _x;
      float _y;
      float _z;
public:
      void point3d_print(){
            printf("%g,%g,%g",_x,_y,_z);
      }
};

class A{};         // sizeof(A) = 1  有木有很奇怪？稍后说明
class B{int x;};   //  sizeof(B) = 4
class C{
      int x;
public:
      int get(){return x;}
};                 //  sizeof(C) = 4; 是不是验证了我们上述的论述？

A a,b;
if(&a == &b)cout<<"error"<<endl;

class A{
	char x;
	int y;
	char z;
};  // sizeof(A) == 12;
class B{
	char x;
	char y;
	int z;
};  // sizeof(B) = 8;
class C{
	int x;
	char y;
	char z;
};  // sizeof(C) = 8;
class D{
	long long x;
	char y;
	char z;
};  //sizeof(D) = 16; 由于longlong为8字节大小，此处以8字节对齐

class A{
	static int x;
};  //sizeof(A) = 1;
class B{
	int x;
public:
	int get(){
		return x;
	}
};  //sizeof(B) = 4
class C{
	int x;
public:
	virtual int get(){
		return x;
	}
};  //sizeof(C) = 8;

class A{
	void (*pf)(); //函数指针
};   //sizeof(A) = 4;
class B{
	int *p;   // 指针
};   //sizeof(B) = 4;

class X{
	int a;
	int b;
public:
	virtual void foo1(){cout<<"X::foo1"<<endl;}
	virtual void foo2(){cout<<"X::foo2"<<endl;}
};

#include<iostream>
using namespace std;
class X{
	int _a;
	int _b;
public:
	virtual void foo1(){cout<<"X::foo1"<<endl;}
	virtual void foo2(){cout<<"X::foo2"<<endl;}
};
typedef void (*pf)();
int main(){
	X a;
	int **tmp = (int **)&a;
	pf ptf;
	for(int i=0;i<2;i++){
		ptf = (pf)tmp[0][i];
		ptf();
	}
}

class A{
      int x;
};
class B:public A{
      int y;
};   //sizeof(B) = 8;

class C{
public:
	virtual void fooC(){
		cout<<"C::fooC()"<<endl;
	}
};  //sizeof(C) = 4;
class D:public C{
	int a;
public:
	virtual void fooD(){
		cout<<"D::fooD()"<<endl;
	}
};  //sizeof(D) = 8;

typedef void (*pf)();
int main(){
	C a;
	D b;
	int **tmpc = (int **)&a;
	int **tmpb = (int **)&b;
	pf ptf;
	ptf = (pf)tmpc[0][0];
	ptf();
	ptf = (pf)tmpb[0][0];
	ptf();
	ptf = (pf)tmpb[0][1];	
	ptf();
}

class A{
	int _a;
public:
	virtual void fooA(){
		cout<<"C::fooA()"<<endl;
	}
	virtual void poo(){
		cout<<"A::poo()"<<endl;
	}
};  //sizeof(A) = 8;
class B{
	int _b;
public:
	virtual void fooB(){
		cout<<"C::fooB()"<<endl;
	}
	virtual void poo(){
		cout<<"B::poo()"<<endl;
	}
};  ////sizeof(B) = 8;
class C:public A,public B{
	int _c;
public:
	void poo(){
		cout<<"C::poo()"<<endl;
	}
	virtual void hoo(){
        cout<<"C::hoo()"<<endl;
    }
};    //sizeof(C) = 20;

typedef void (*pf)();
int main(){
	C a;
	int **tmp = (int **)&a;
	pf ptf;
	for(int i=0;i<3;++i){
		ptf = (pf)tmp[0][i];
		ptf();
	}
	cout<<"-----------"<<endl;
	int s = sizeof(A)/4; //指针与int都占用4字节大小
	for(int i=0;i<2;i++){
		ptf = (pf)tmp[2][i];
		ptf();
	}
}

class A{
	int _a1;
	int _a2;
};    //sizeof(A) = 8;
class B:virtual public A{
	int b;
};    //sizeof(B) = 16;
class C:virtual public A{
	int c;
};    //sizeof(C) = 16;
class D:public B,public C{
	int d;
};    //sizeof(D) = 28;

int main(){
	D d;
	A *pta = &d;
	B *ptb = &d;
	C *ptc = &d;
	cout<<"D:  "<<&d<<endl;
	cout<<"B:  "<<ptb<<"   C:  "<<ptc<<endl;
	cout<<"A:  "<<pta<<endl;
}